Mitt Romney on Thursday expanded his national lead over President Obama in a key poll, but with less than three weeks left until Election Day, surveys in battleground states that could determine the contest show a tight race.
Romney opened up a 7-point lead among likely voters in the latest Gallup daily tracking poll, gaining 52 percent support to 45 for Obama. Romney also leads 48 percent to 47 among registered voters in the survey.
The survey is a rolling seven-day average through Oct. 17, so it includes one day of polling data since Tuesday night's presidential debate in New York state.
Gallup only began tracking likely voters earlier this month. The 7-point margin is Romney’s biggest lead yet in the survey and comes less than three weeks before the election.
A slew of swing-state polls, though, show many battleground states remain a toss-up.
A NewsMax/Zogby survey of Florida showed the president opening up a 3-point lead in the state, at 47-44 percent support. That poll is a reversal of other Sunshine State surveys released earlier in the week showing Romney with a 1-point edge.
Two polls of Ohio also released Thursday similarly show Obama with a slight edge. A survey from conservative polling outlet Rasmussen puts Obama up 1, at 49 percent support to Romney’s 48 among likely voters in the state. A SurveyUSA poll of registered Ohio voters gives the president a wider 3-point lead.
And a Marquette University Law School poll of Wisconsin released Wednesday showed Obama leading 49-48 percent in the Midwestern battleground.
Democrats are hopeful Obama’s forceful performance in the Tuesday night debate this week will be enough to blunt Romney’s momentum, buoyed by the tightening battleground numbers.
The first debate between the two presidential contenders, on Oct. 3, significantly altered the race's momentum and propelled Romney to his first national leads of the election cycle and helped him close the gap in many swing states.
But since the debate, Republicans have shown increasing optimism that Romney can win Virginia, Florida and North Carolina.
Real Clear Politics recently moved Michigan, Pennsylvania and Wisconsin from “lean Obama” to “toss-up,” although Romney still has his work cut out for him in those states.
Other states, such as Iowa, Colorado and Ohio, are currently deemed true toss-ups by both campaigns.
Furthermore, Gallup's daily tracking poll is subject to day-to-day fluctuations and could be an outlier. Romney leads Obama by less than 1 percentage point, 47.4 to 46.9, in the Real Clear Politics average of national polls.
Gallup polls only survey registered voters early in the cycle, but as Election Day nears, the firm is prodding for more information from voters to determine the likelihood that a registered voter will end up casting a ballot. Many believe surveys of likely voters are more accurate than those that only survey registered voters.
However, Gallup noted that sometimes, such as in 2008, “there was only a marginal difference between the vote choices of registered voters and likely voters,” while other times, such as in 1996, “there was a much more substantial difference.”
The Gallup poll has a margin of error of 2 percentage points.
—This story was first published at 1:13 p.m. and has been updated.